Archived posting to the Leica Users Group, 2013/01/29

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Subject: [Leica] DOF Tables.....
From: cedric.agie at gmail.com (Cedric Agie)
Date: Tue, 29 Jan 2013 21:02:54 +0100
References: <072d01cdfd1c$3245cfc0$96d16f40$@verizon.net> <BLU0-SMTP963C8F51BE1B7691B136D38C180@phx.gbl> <084301cdfd68$c50508c0$4f0f1a40$@verizon.net> <CABmfTOUGCt=z1Z3-iLZ8-Sae81QutxwS1fSKkj0F04Ww=QXy0w@mail.gmail.com>

I have (plasticized) cards with DOF charts for all the lenses I've
got. As well for Leica as for Hasselblad. When in doubt, for example
with a tele or a macro set-up, I always have them at hand and I check
them before taking some pictures. Be it portraits, flowers or insects
etc. It's too bad to discover that the nose, the eyes of the girl, the
bird or the insect etc are out of focus when they are gone. In
practice forget MFT arguments, because for you they are useless. It's
good for the optical engineers to conceive and check the lenses they
produce...... check what the others are doing or for the people of the
sales department who don't always know what to say to sell their so
called new and better products. Also forget arguments such as cit;
".... small residual optical faults corrected in the camera
software....".

It takes some thinking and time to calculate or check these DOF charts
for the lenses you've got. But do it, it's a good exercise. Sometimes
you'll discover strange things or funny phenomenon's and even mistakes
that went unnoticed for 10's of years. Even in Leica (Leitz) or Zeiss
letterature. You'll know your lenses much better. And by the way, when
you're reading articles or hear arguments, you'll soon discover if the
guy really knows what he is talking about. In the end it will stay
somewhere in the back of your mind. That makes the difference between
an  even talentfull amateur and a very good professional photographer.
The pro will take one or two pictures. Some amateurs will show you the
one picture he or she took almost by chance and not the others.

Is it really necessary to pay almost two times the price of a lens for
an increase of just one stop and a DOF that is suddenly reduced to
centimetres or millimetres? For macro follow this rule: fully close
the opening of your (best) lens and then open it one stop. And check
it's DOF. To the contrary of what some say, digital photography hasn't
changed these basic rules.

Are your really going to walk around in daylight with a Noctilux 0.95
and a speed of 400 ISO or more? Or is it just for fun? When you do
these calculations you really start thinking. And do take notes of
your new tests.

On the other hand I know (a very few) pro's who can walk around at
night in a city, in a bar, around an orchestra or a theatre, inside
it's buildings and take pictures in dim light, going unnoticed and
come back with marvellous pictures.

cedric.agie at gmail.com






2013/1/28 Marty Deveney <benedenia at gmail.com>:
> On Tuesday, 29 January 2013, Frank Filippone wrote:
>
>> True, but note that the 90, at F2 , has the same limited DOF as the 75 at
>> F1.4.
>>
>> We do not hear too much about difficulty with focusing the 90.....  I
>> wonder
>> why not?
>>
>
> My principal difficulties with the 75 Summilux occur closer than the 90
> focuses, in the extremely shallow dof range under 1 m.
>
> Marty
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information


Replies: Reply from kanner at acm.org (Herbert Kanner) ([Leica] DOF Tables, or a tiny bit of physics)
Reply from mark at rabinergroup.com (Mark Rabiner) ([Leica] DOF Tables.....)
Reply from mark at rabinergroup.com (Mark Rabiner) ([Leica] DOF Tables.....)
In reply to: Message from red735i at verizon.net (Frank Filippone) ([Leica] DOF Tables.....)
Message from vick.ko at sympatico.ca (Vick Ko) ([Leica] DOF Tables.....)
Message from red735i at verizon.net (Frank Filippone) ([Leica] DOF Tables.....)
Message from benedenia at gmail.com (Marty Deveney) ([Leica] DOF Tables.....)